Apparatus and method for tissue removal

ABSTRACT

Percutaneous tissue removal apparatus comprises a flexible drill shaft, a cutting tip mounted on the shaft for placement adjacent a tissue mass for cutting the tissue, means for transmitting motion to the shaft to move the cutting tip against the tissue to cut tissue fragments from the tissue, and means for removing the tissue fragments along the shaft by suction to a location outside the tissue mass while cutting. The apparatus may include means for collecting one or more selected components of the harvested tissue fragments for implantation of the fragments preferably into the body of the patient from whom they were removed. Where the tissue to be cut is bone, a cutting tip is preferably made of a polymeric material which is softer than the cortical portion of the bone, although the cutting tip may be made of a ceramic or a composite material. A second flexible shaft may be provided either within or about the flexible drill shaft. The harvested tissue fragments may be implanted in the donor patient&#39;s body.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to the field of tissue removal andtissue grafting. More particularly, the present invention relates to anapparatus and method for the percutaneous cutting and removal ofselected portions of tissue from a patient and the possible harvestingand implantation of the tissue portion in the donor.

[0003] 2. Description of the Prior Art

[0004] There are various known methods and apparatus for the cutting andremoval of tissue fragments from a human. Each of these, however,suffers from one or more deficiencies.

[0005] U.S. Pat. No. 4,832,683 shows an instrument for ultrasoniccutting of bones, with irrigation or suction. However, there is nosuction while cutting, no removal of the cut bone or tissue, and noflexibility in the instrument.

[0006] U.S. Pat. No. 4,265,231 shows apparatus for drilling a curvedhole having a flexible shaft confined in a rigid tubular sheath, butwhich shows no removal of cut bone or tissue.

[0007] U.S. Pat. No. 4,541,423 shows apparatus for drilling a curvedhole having a flexible shaft confined in a semi-rigid tubular sheath,but which shows no removal of cut bone or tissue.

[0008] U.S. Pat. No. 4,589,414 shows a surgical cutting instrument witha reciprocatory cutting motion, but which has no removal of cut bone ortissue, and no flexibility in the instrument.

[0009] U.S. Pat. No. 4,603,694 shows a rotating arthroscopic shaver withsuction, but which is not flexible and which has no removal of cut boneor tissue.

[0010] U.S. Pat. No. 4,751,922 shows a flexible medullary reamer with aplastic shaft and a guide rod, but which has no suction and no removalof the cut bone or tissue.

[0011] U.S. Pat. Nos. 4,798,213, 4,649,918, and 4,142,517 show variousapparatus for bone coring.

SUMMARY OF THE INVENTION

[0012] The present invention is a percutaneous tissue removal apparatusincluding a flexible drill shaft and means for transmitting motion tothe shaft. A cutting tip is mounted on the shaft to cut tissue fragmentsfrom the tissue. The tissue fragments are removed by suction along theflexible drill shaft to a location outside the body while cutting. Oneor more selected components of the removed tissue fragments may becollected for implantation, preferably into the body of the patient fromwhom they were removed. Because the drill shaft is flexible, the surgeoncan guide the cutting tip into various locations within the tissue froma small (percutaneous) incision. The surgeon can cut around arcs orangles, rather than only being able to go in a straight line, to reachany desired location, and to avoid vital tissue which would otherwise bein the cutting path. For example, when removing unwanted tissue inside aknee joint the drill shaft can deform, and is therefore less likely todamage normal tissue or joint surfaces. None of these functions ispossible with a straight line system.

General Description of the Invention

[0013] The present invention is a percutaneous tissue removal device andmethod. In the preferred embodiments described below, the apparatus andmethod are illustrated as used for removal of bone tissue, but suchdescription is for illustrative purposes only. The invention is notlimited to the removal of bone tissue and may be used for removal ofcartilage, muscle, fetal tissue, etc. It may be used to break up andremove kidney stones, in the gall bladder for a stone or tumor, in thestomach, in the colon to remove a polyp or tumor, etc. It can reachspaces not currently available with the straight line systems currentlyavailable.

[0014] A percutaneous tissue removal apparatus in accordance with thepresent invention includes a flexible drill shaft for insertion inside atissue. A cutting tip is mounted on the drill shaft for cutting thetissue. Either rotating motion or reciprocating motion is transmitted tothe drill shaft to move the cutting tip against the tissue to cut tissuefragments from the tissue. While cutting, the tissue fragments areremoved by suction to a location outside the body. The drill shaft andcutting tip are small enough to be usable percutaneously. They may alsobe used for endoscopic, arthroscopic or fiberoptic or open surgery.

[0015] Because the drill shaft is flexible, the surgeon can guide thecutting tip into various locations within the tissue from onepercutaneous incision. The surgeon can cut around arcs or angles, ratherthan only being able to go in a straight line, to reach any desiredlocation, and to avoid vital tissue which would otherwise be in thecutting path. The flexible drill shaft also allows the surgeon whenworking inside a bone, for example, to keep the cutting tip away fromthe harder outer cortical bone and to remove only the softer innercancellous bone. None of these features is available with the currentstraight line cutting devices.

[0016] The drill shaft may be made of metal, of polymeric material toreduce friction, or of a composite material. Extensive use of polymersin the drill shaft, its housing if provided, and the cutting tip areareduces friction substantially, thus requiring less energy andgenerating less heat within the tissue. The drill shaft is drivable byhand (for improved feel) or by motor, at variable speeds based on theneed for the tissue removed.

[0017] To provide for the collection of the tissue fragments to beharvested, the removal apparatus has an axially extending suctionpassage along the drill shaft through which the tissue fragments areremoved. The suction passage has a smooth lining to keep the tissuefragments or graft material contained and to reduce friction of theharvested tissue fragments. This lining may be the inside diameter ofthe flexible drill shaft itself, or may be a separate liner sleeve whichcan be removed and disposed of when it becomes unsanitary or clogged,without having to remove the drill shaft and cutting tip. Alternatively,if a separate guide sleeve or guide rod is used the suction passage maybe formed between the drill shaft and the guide sleeve or guide rod. Insuch a case, the drill shaft may be solid rather than hollow.

[0018] The cutting tip is made of a material which is harder than thematerial to be cut. The cutting tip may be slightly larger in diameterthan the drill shaft. The cutting tip may be made of a polymericmaterial or a composite material. Alternatively, the cutting tip may bemade of a ceramic material. The cutting tip is separable from the drillshaft, and several different cutting tips may be provided in varyinghardnesses, so that the surgeon can selectively remove various portionsof tissue as desired.

[0019] By virtue of its flexibility, the flexible drill shaft, whenremoving bone tissue, may stay within the cortical confines of the bone.Alternatively, it may work with a guide device to control the locationof the cutting tip within the bone. The guide means may be a guide rodextending within the flexible drill shaft, or a hollow guide sleeveoutside the flexible drill shaft. The guide rod or guide sleeve may berigid in a particular shape, to fit a particular application; or it maybe bendable into a particular shape which it will hold; or it may beselectively rigidifiable into a particular shape in situ. The guidemeans may include structure for positioning the tip of the flexibledrill shaft. The guide means may also be inserted into a separateflexible tube system to guide it to a specific location, then removed,allowing the flexible drill to be inserted.

[0020] Fluid may be injected through the flexible drill shaft to alocation adjacent the cutting tip to increase the efficiency of thetissue removal and to limit thermal necrosis. Alternatively, a fluidinjection passage may extend axially along the flexible drill shaft, thedrill shaft. Alternatively, fluid may be injected through the suctionpassage, alternating with the suction. The fluid injection may beconstant or it may be pulsatile in nature. If fluid injection is used,centrifuging of the harvested material may be performed.

[0021] Means for collecting one or more selected components of theharvested tissue fragments may include a known trap or filter connectedto the outlet of the suction passage. Removed tissue may be centrifugedto separate its components. Thus, the tissue fragments are not merelyremoved from the body and may be harvested for implantation of thefragments, preferably into the body of the patient from whom they wereremoved. In order to maintain the sterility of the tissue removed, theentire suction apparatus including the suction passage and the trap orfilter is sterilized, and, if necessary, is disposable.

[0022] With the present invention all work is done by goingpercutaneously through the skin to a specific tissue area to minimizethe damage to skin, muscle, and bone. For example, when removing bonetissue, trauma is limited to a small opening in the hard outerstructural cortical bone, limiting postoperative bleeding from the bonewhich is difficult to stop, because the small operative hole can easilybe plugged after the grafting procedure is completed, preventingpostoperative bleeding into soft tissue. There is only intraosseousbleeding, so that fewer complications, and less pain, are likely toarise. The operation does not create stress risers which would weakenthe bone. Thus, the present invention provides a safe and efficient wayto collect and reuse a patient's own tissue.

[0023] Human tissue grafting works best using the patient's own tissueas donor material. Therefore, the harvested tissue may be implanted inthe donor's own body for grafting. To implant one or more selectedcomponents of harvested bone fragments, for example, a cannula isinserted through the skin and muscle to the area of the bone where thegraft is to be placed. A drill or curette is then used to remove aportion of the outer cortical bone. A curette or probe is insertedthrough the cannula to clear out the area where the graft is to beplaced, either in open surgery or through X-ray guidance in percutaneoussurgery. The harvested tissue fragments may be packed or compressed intoa plug of tissue graft material, of a specific shape, with or withoutblood or fibrin for adhesion. Or, a retaining material such as abiodegradable mesh may be used to hold the graft material together as aunit. The graft material and its retaining material are then inserted atthe graft location in the bone. Alternatively, the graft material isinserted and then sealed in place with a mass of formable polymericmaterial inserted over the graft material to hold the graft together inposition.

[0024] A method of percutaneous tissue removal in accordance with thepresent invention includes the steps of placing within a tissue mass aflexible drill shaft having mounted thereon a cutting tip for cuttingthe tissue; transmitting motion to the drill shaft to move the cuttingtip against the tissue to cut tissue fragments from the tissue; andremoving the tissue fragments by suction to a location outside thetissue mass while cutting the tissue. The method may further include thestep of controlling the location of the cutting tip within the tissuewith a guide rod, the step of collecting one or more selected componentsof the harvested tissue fragments, and/or the step of implanting thefragments into the body of the patient from whom they were removed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further features of the present invention will become apparent tothose skilled in the art to which the present invention relates fromreading the following specification with reference to the accompanyingdrawings, in which:

[0026]FIG. 1 is a schematic view of a tissue removal system inaccordance with the present invention and including a flexible drill;

[0027]FIG. 2 is a schematic view of a hand-powered flexible drill foruse in the system of FIG. 1;

[0028]FIG. 3 is a schematic view of a portion of a hollow flexible driveshaft for the flexible drill;

[0029]FIG. 4 is a schematic view similar to FIG. 3 and showing a guiderod inside the hollow flexible drive shaft;

[0030]FIG. 5 illustrates a portion of a flexible drill including ahollow flexible inner cutting shaft within a flexible outer sleeve and asuction passage between the two shafts;

[0031]FIG. 6 is a view similar to FIG. 5 with a suction passage withinthe inner shaft;

[0032]FIG. 7 illustrates a portion of a flexible drill including a solidflexible inner cutting shaft within a flexible outer sleeve and asuction passage between the two shafts;

[0033]FIG. 8 illustrates a portion of a flexible drill including a solidformable inner guide rod within a flexible outer cutting sleeve and asuction passage between;

[0034]FIG. 9 illustrates a portion of a flexible drill including ahollow flexible inner cutting shaft within a solid formable outer sleeveand a suction passage between;

[0035]FIG. 10 is a view similar to FIG. 9 with a suction passage withinthe inner shaft;

[0036]FIG. 11 illustrates a portion of a flexible drill including asolid flexible inner cutting shaft within a solid formable outer sleeveand a suction passage between;

[0037]FIG. 12 illustrates a portion of a flexible drill including arelatively flexible portion between two relatively rigid portions;

[0038]FIG. 13 illustrates the use of a liner sleeve in a suctionpassage;

[0039]FIG. 14 is a view illustrating a number of different cutting tipsusable with the flexible drill;

[0040]FIGS. 15 and 16 are schematic views illustrating the provision ofa plurality of separately inflatable bladders as a guide mechanism for aflexible structure and the operation of a guidance system for locatingthe tip of the flexible structure;

[0041]FIGS. 17 and 17A are schematic views illustrating the forming ofharvested tissue fragments into a compressed plug suitable forimplantation;

[0042]FIG. 18 is a schematic view illustrating the implantation ofharvested bone fragments using a polymeric mesh as a retainer; and

[0043]FIGS. 19 and 19A are schematic views illustrating the implantationof harvested tissue fragments using a formable polymeric sealant as aretainer.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0044] The present invention is described herein with reference to apercutaneous bone removal and harvesting apparatus and method. It shouldbe understood that the present invention is not limited to the removalof bone tissue, but is useful in the removal of any hard or soft tissuein the body such as excess, unwanted, or tumorous tissue or tissue usedfor reimplantation or grating.

[0045] A percutaneous bone removal apparatus 10 (FIG. 1) in accordancewith the present invention includes a flexible drill 12. The flexibledrill 12 has a flexible shaft 14 and a cutting tip 16 at the distal endof the shaft 14. The proximal end of the flexible shaft 14 is connectedby a housing 18 to a motor or other power source 20 to providerotational motion or reciprocating motion in a manner known in the art.Alternatively, the drill 12 may have an angled drive, such as 90° driveor any angle, with the motor drive connected at an angle to thelongitudinal extent of the suction and cutting apparatus.

[0046] Control means indicated schematically at 21 may include one ormore switches or valves to turn on or off the suction, irrigation, andmotor drive. control A fluid injection source 22 is connected by a fluidinjection line 24 to the housing 18 of the flexible drill 12. A suctionsource 26 acts through a trap or filter or strainer 28 and a suctionline 30 to provide suction capabilities for the flexible drill 12.

[0047]FIG. 2 illustrates a flexible drill 12 a in which the housing 18 ais connected to a hand controller 20 a. The hand controller 20 a allowsthe surgeon to operate the flexible drill 12 a by hand, imparting eitherrotational or reciprocating movement to the flexible shaft 14 a andcutting tip 16 a.

[0048]FIG. 3 illustrates a portion of a basic version of a flexibledrill having a cutting tip 16 mounted on a flexible drive shaft 31. Thedrive shaft 31 has an outer surface 32 and an inner surface 34 defininga longitudinally extending suction passage 36. The cutting tip 16 has acutting edge 40 and an opening 38 through which tissue fragments cut bythe cutting tip 16 may be aspirated. The tissue fragments are drawnthrough the suction passage 36 in the flexible drive shaft 31 and thenceinto the suction line 30 (FIG. 1) for collection in the trap or filteror strainer 28.

[0049]FIG. 4 illustrates the use of a pre-inserted guide rod 42 with aflexible drill of the present invention. The guide rod 42 extendsthrough the suction passage 36 of the flexible drive shaft 31. The guiderod 42 may be any suitable structure including a K-wire or other knowndevice. The cutting tip 16 may have a centrally located opening in itsdistal end to allow insertion of the flexible drill over the guide rod42. The guide rod 42 is first placed in the body, then the flexibledrill is inserted over the guide rod 42 and guided to the location fromwhich tissue is to be harvested.

[0050]FIG. 5 illustrates an embodiment of a flexible drill having anouter sleeve 44 circumscribing a flexible drill shaft 41. The flexibleouter sleeve 44 may be formed of a metal or composite material or may beformed of a polymeric material which may be the same as or differentfrom the material of the flexible inner cutting shaft 31. The outersleeve 44 is fixed (non-moving) to minimize tissue damage. A suctionpassage 46 is defined between the outer surface of the flexible innershaft 31 to which the cutting tip is attached, and the inner surface ofthe flexible outer sleeve 44. Alternatively, as shown in FIG. 6, asuction passage 48 may be defined within the flexible inner cuttingshaft 50. In this case, the outer surface of the flexible inner shaft 50is preferably, as illustrated in FIG. 6, in close proximity to the innersurface of the outer sleeve 44 to increase stability. The use ofpolymeric materials for both the inner shaft 50 and the outer sleeve 44provides for reduced friction between the sleeve 44 and the shaft 50 forease of operation and reduced heat generation.

[0051]FIG. 7 illustrates an alternate embodiment of the apparatus ofFIG. 5 in which the flexible inner cutting shaft 52 is formed as a solidshaft rather than a hollow shaft. The harvested tissue fragments travelthrough the suction passage 46 between the inner shaft 52 and the outersleeve 44.

[0052]FIG. 8 illustrates apparatus similar to FIG. 7 in which a fixed(non-moving) inner shaft 54 is made of a solid, formable, material andthe cutting tip is mounted on a flexible rotating outer sleeve 56.Suction is drawn through a suction passage 58 between the shaft 54 andthe sleeve 56. The inner shaft 54 is made from a semi-rigid materialwhich is bendable to a desired curvature, at the use site, to select thecurvature of the hole to be drilled, and which is rigid enough to retainthat curvature in use while the drill shaft 56 rotates around it. Suchmaterial is disclosed in U.S. Pat. No. 4,541,423, the disclosure ofwhich is incorporated herein by reference.

[0053]FIGS. 9, 10 and 11 illustrate embodiments of the flexible drill ofthe present invention in which a flexible inner cutting shaft, which maybe hollow or solid, is disposed within a non-moving formable outersleeve. The formable outer sleeve 60 is made of a semi-rigid bendableshape retaining material as described above with reference to FIG. 8. InFIG. 9, a hollow flexible inner cutting shaft 62 is disposed within theouter sleeve 60 and defines therebetween a suction passage 64. In FIG.10, a hollow flexible inner cutting shaft 66 is disposed in closeproximity to and within the outer sleeve 60, with a suction passage 68formed within the flexible inner cutting shaft 66. In FIG. 11, a solidflexible inner cutting shaft 70 is disposed within the outer sleeve 60,defining therebetween a suction passage 72.

[0054]FIG. 12 illustrates a portion of a flexible drill shaft 80 inaccordance with the present invention in which a pair of relativelyrigid drill portions 82 and 84 are joined by a relatively flexible drillportion 86. The relatively rigid drill portion 82 includes an outersleeve 88, an inner shaft 90, and a suction passage 92 therebetween. Therelatively rigid drill portion 84 includes an outer sleeve 94 like theouter sleeve 88, an inner shaft 96 like the inner shaft 90, and asuction passage 98 therebetween. The drill portion 86 includes arelatively flexible inner shaft portion 100 disposed within a relativelyflexible outer sleeve portion 102, defining therebetween a suctionpassage 104. The relatively flexible inner shaft portion 100 connectsthe relatively rigid inner shaft portions 90 and 96. The relativelyflexible outer sleeve portion 102 connects the relatively rigid outersleeve portions 88 and 94. The suction passage 104 in the relativelyflexible drill-shaft portion 86 connects the suction passages 92 and 98.Either the inner shaft or the outer sleeve of the flexible drill 80 mayhave a cutting tip mounted thereon. Thus, with a flexible drill shaftmade in this manner, it is not necessary that the entire drill shaft bemade of flexible materials, but rather “joints” such as are formed bythe relatively flexible portion 86 may be placed along the longitudinalextent of a relatively rigid drill shaft as desired.

[0055]FIG. 13 illustrates how a disposable single-use liner sleeve 110may be used in a flexible drill of the present invention. The linersleeve 110 shown in FIG. 13 is located within an outer sleeve 112 and isshown about a guide rod or guide wire 114. Suction is drawn through apassage 116 within the liner sleeve 110. The disposable single-use linersleeve 110 provides an absolutely sterile environment through whichharvested tissue fragments may pass. The inner surface 118 of the linersleeve 110 is extremely smooth in order to facilitate passage of theharvested tissue fragments therethrough. It should be understood that aliner sleeve like the liner sleeve 110 may be used with any suitableflexible drill shaft configuration in accordance with the presentinvention, and not merely with the configuration shown in FIG. 13.

[0056]FIG. 14 illustrates several different cutting tips which may beattached in a known manner to a flexible drill shaft in accordance withthe present invention. The technology for the cutting tips is notspecific to the present invention, but rather the cutting tips may bedesigned in accordance with known principles.

[0057] The cutting tip 120 (FIG. 14) has a cutting edge 122 at leastpartially defining an opening 123 through which suction is drawn. Thecutting tip 124 includes a plurality of cutting edges 126 defining aplurality of suction openings 128 disposed along the outercircumferential portion of the cutting tip 124. The cutting tip 130 issimilar to the cutting tip 124 but includes cutting edges 126 a andsuction openings 128 a which extend to the end of the cutting tip 130.Furthermore, the cutting tip 130 is blunt rather than sharp, to avoidperforation of tissue, such as bones.

[0058] The cutting tip 132 has a spiral cutting edge 134 defining aspiral suction opening 136. The cutting tip 138 has at least onelongitudinally extending cutting edge 140 at least partially defining alongitudinally extending suction opening 142. The cutting tip 143 isformed as a burr with fluted cutting edges 144 and suction openings 145,and is especially suited for shaving operations such as removal of bonespurs, etc. The cutting tip 146 has twin cutting edges 147 and 148 and asuction opening 149. The cutting edges 157 and 148 can be configuredwith the leading edge to grab the tissue and the trailing edge to cutthe tissue.

[0059] The configuration of a cutting tip for use in accordance with thepresent invention is a design choice within the skill of the art. Thegoals to be met are proper cutting and suction capabilities,controllability and shape so as to avoid unwanted damage to areas oftissue not to be cut. For example, when removing the softer cancellousportion of bone, the cutting tip may be made of a material which isharder than the cancellous material of the bone but softer than thecortical portion of the bone to avoid damage thereto. Metal may beuseful, and suitable polymers are also readily available. Ceramicmaterials and composites are also suitable. Also, the cutting tip may bearranged as a rotating flexible shaft within a fixed flexible outershaft, with a cutting edge on the rotating shaft to cut tissue offagainst the fixed edge. In such a case, the apparatus may beadvantageously configured with one shaft being metal and the otherpolymeric, to minimize friction and heat buildup.

[0060]FIGS. 15 and 16 illustrate an alternate guidance system forpositioning a flexible drill shaft 150 and its associated cutting tip.Disposed within the sleeve 150 is a guidance mechanism 152 including aplurality of inflatable elements spaced serially. The inflatableelements, when inflated, rigidify and become straight, while when in thedeflated condition they are soft and flexible and may be curved or bent.Thus, as seen in FIG. 15, both the inflatable elements designated 154and the inflatable elements 156 are curved. In FIG. 16, the inflatableelements 154 have rigidified and straightened, while the inflatableelements 156 remain in their curved position. The inflatable elementsmay also be accordion shaped, expanding in length as they are inflated.The mechanism 152 may be augmented with a known cable guidance system.

[0061] By selectively and individually controlling the rigidification ofany or all of the inflatable elements of the mechanism 152, theinflatable mechanism 152 and its associated outer sleeve 150 may beselectively formed into almost any desired shape or position. Suitablecontrol and valving apparatus is provided for controlling the inflationof the inflatable elements. Such apparatus may be, when only a fewelements are present, a simple mechanical valving apparatus. When moreelements are present, or more sophisticated or complex control thereofis desired, a microprocessor may be used to control the inflation ofeach segment. Separate inflation and deflation lines can be used, or oneline can, by alternating valving, serve both functions. In such case,the control signals may be multiplexed down the structure via electricwire, optical fiber, or radio control, for example.

[0062] At the distal end of the mechanism 152 is a tip guidancemechanism 160 including a plurality of inflatable members 162. Theinflatable members 162 when in a deflated condition are flexible andrelatively straight. When inflated, as shown in FIG. 16, the members 162assume a preformed shape which may be curved or straight and which isillustrated herein as a curved shape, bending radially outwardly toengage the surface of adjacent tissue 164 and curve the end of thedevice into an appropriate position. The members 162 may be constructed,using known principles, to assume any desired shape. By controlling thepositioning of one or more of the elements 162, the tip portion 168 ofthe guidance mechanism 152 may be selectively placed in any positionrelative to the tissue 164, thus positioning the end of the sleeve 150.The air bladder guidance system as described may be used in conjunctionwith a flexible tube separate from the flexible drill shaft, order toguide the flexible tube to a specific location and position it there,thereafter removing the guidance system and allowing a flexible drill tobe inserted.

[0063] Means for collecting one or more selected components of theharvested tissue fragments includes a mechanism 28 (FIG. 1) which may bea known trap or filter connected to the outlet of the suction passage30. Removed tissue may also be centrifuged if necessary or desired,keeping the components such as bone, cells, and blood and discardingfluid. These components and connections, and their uses, are well knownin the art and thus are not described herein in greater detail. Theharvested tissue fragments are not merely removed from the body of thepatient, but are also collected in the structure 28 and thus harvestedor saved for later implantation of the fragments, preferably into thebody of the patient from whom they were removed. Such harvesting andimplantation are desirable because human tissue grafting works bestusing the patient's own tissue as donor material.

[0064] In preparing the harvested graft material for implantation, thetissue fragments alone are spun or compressed (see FIG. 17) to form theminto the desired shape. When the tissue is harvested, blood and bloodclots are often drawn along with the tissue fragments. The bloodcomponent fibrin is a sticky clotting component, and can be used to aidin holding the tissue fragments together for implantation. Thus, theblood can be is separated from the tissue fragments and then spun toseparate the fibrin for use with the tissue fragments. Alternatively,the entire mass of tissue fragments and blood is compressed into aspecific shape to form the mass into a specific, appropriate shape forimplantation into the body.

[0065] The surgeon can also place other substances into the graftmaterial to be implanted, such as other tissue graft material, collagen,antibiotics, or ceramic hydroxyapatite or tricalcium phosphate to aid inbone ingrowth. In such a case, when the blood or fibrin is used also,the graft has the adhesive qualities of the blood or fibrin and thebiological properties of the bone (or other) tissue, along with theappropriate medical properties of any other material included.

[0066] Harvested tissue fragments before implantation are preferablypacked or compressed into a plug of tissue graft material.Alternatively, the tissue fragments may be left in a more loose state,or only certain selected cells, components, or tissue fragments areused. Any suitable means of packing or compressing fragments may beused. FIG. 17 illustrates schematically a simple apparatus for doing so.As viewed in FIG. 17, the harvested tissue pieces 170 are placed into aform or mold 172 and then compressed by a movable compressor 174 to forma plug 176 of a desired shape or size. Unwanted fluid drains out throughone or more fluid outlets 178, while the graft, cells, fibrin, and bloodclot tissues remain within the form 172.

[0067] To implant one or more selected components of the harvestedtissue fragments, for example in grafting bone tissue onto a bone, acannula 180 is inserted through the skin 182 and muscle 184 to the areaof the bone 186 where the graft is to be placed. A curette or probe isthen inserted through the cannula 182 to clear out the area 188 wherethe graft is to be placed.

[0068] The harvested tissue fragments are compacted or compressed into aplug 190 of tissue graft material. A retaining material such as a knownbiodegradable or other polymeric mesh 192 is then used to hold the graftmaterial 190 together as a unit. The retaining material may also be asac of biodegradable material used to hold the graft material. The saccan be closed by a clamp or by crimping or heat sealing. The graftmaterial 190 and its retaining material 192 are then inserted into thegraft area of the bone. The cannula 180 may then be removed.Alternatively, the tissue graft material may be held in place by a massof biodegradable or other polymeric material used as a sealant for theopening in the bone 186. The graft material can be compressed or spuninto a specific shape. Thus, if an implant is needed to fit a specificshape of bone defect, the graft material can be formed in the shapeneeded and packed directly into the bone gap.

[0069] The bone graft material may also be implanted in the loosecondition as described above. The bone graft material 194, if loose, canbe inserted through a funnel 196 and a sleeve 198 located within thecannula 180, to the area 188 to be grafted. It is then packed in placeas desired using a suitable instrument. Next, an injector 200 is used toinject a mass of flowable biodegradable or other polymeric material 202for use as a sealant to seal the bone graft material 194 in position.The use of a flowable biodegradable material is preferable in that itallows the surgeon to form in situ a custom shaped sealant plug to sealthe opening in the tissue graft area, which will eventually resorb asnew tissue grows into its. place.

[0070] The apparatus may include, as noted above, fluid injection means22 and 24 for injecting fluid through the flexible drill to a locationadjacent the cutting tip to aid in cutting and removal of the harvestedtissue fragments. For example, in the drill shaft structure illustratedin FIG. 5, fluid may be injected through a fluid injection passage 204within the flexible inner cutting shaft 31, while suction is drawn inthe opposite direction through the suction passage 46. Alternatively,the suction may be intermittently discontinued and fluid may be injectedthrough the suction passage, alternating with the suction. The fluidinjection may be constant or it may be pulsatile in nature.

[0071] The present invention thus provides a method of percutaneoustissue removal which includes the steps of placing adjacent to a tissuemass a flexible drill shaft 14 having mounted thereon a cutting tip 16for cutting the tissue; transmitting motion to the drill shaft 14 tomove the cutting tip 16 against the tissue to cut tissue fragments fromthe tissue; and removing the tissue fragments by suction to a locationoutside the tissue mass while cutting the tissue. The method may furtherinclude the step of controlling the location of the cutting tip withinthe tissue with a guide mechanism, the step of collecting one or moreselected components of the harvested tissue fragments, and/or the stepof implanting the fragments into the body of the patient from whom theywere removed.

[0072] From the above description of the invention, those skilled in theart will perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

I claim:
 1. Tissue removal apparatus comprising: a flexible drill shaft;a cutting tip mounted on said shaft for cutting tissue; means fortransmitting motion to said shaft to move said cutting tip against thetissue to cut tissue fragments from the tissue; and means for removingthe tissue fragments along said shaft by suction to a location outsidethe body while cutting.
 2. An apparatus as defined in claim 1 includingmeans for collecting one or more selected components of the removedtissue fragments for implantation of the fragments into the body of thepatient from whom they were removed.
 3. An apparatus as defined in claim1 wherein said drill shaft comprises a polymeric or composite material.4. An apparatus as defined in claim 1 wherein said cutting tip comprisesa polymeric or composite material with hardness specific to tissueapplication.
 5. An apparatus as defined in claim 2 wherein said cuttingtip is made of a composite or ceramic material.
 6. An apparatus asdefined in claim 1 wherein said flexible drill includes surface meansdefining a suction passage extending axially along said drill shaftthrough which said bone fragments are removed, said suction passagehaving a smooth polymeric surface to reduce friction.
 7. An apparatus asdefined in claim 1 further including guide means for controlling thelocation of said cutting tip within the tissue.
 8. An apparatus asdefined in claim 7 wherein said guide means comprises a guide rodextending within said flexible cutting shaft to allow said shaft toadvance into a space.
 9. An apparatus as defined in claim 8 wherein saidguide means is selectively rigidifiable.
 10. An apparatus as defined inclaim 1 including means for injecting fluid to a location adjacent saidcutting tip including surface means defining a fluid injection passageextending axially along said flexible shaft.
 11. An apparatus as definedin claim 1 wherein said flexible drill shaft is hollow and comprising anon-moving flexible sleeve extending generally coaxially about saidflexible drill shaft.
 12. An apparatus as defined in claim 11 includingan axially extending suction passage between said flexible drill shaftand said flexible sleeve and through which the tissue fragments areremoved.
 13. An apparatus as defined in claim 1 wherein said flexibledrill shaft is solid and comprising a flexible sleeve extendinggenerally coaxially about said flexible drill shaft and movable withsaid flexible drill shaft when said flexible drill shaft is moved to cuttissue.
 14. An apparatus as defined in claim 1 comprising a formablesleeve extending generally coaxially with said flexible drill shaft. 15.An apparatus as defined in claim 1 comprising a disposable liner sleeveat least partially defining a suction passage for the harvested tissuefragments.
 16. Tissue removal apparatus comprising: a flexible shaft; acutting tip mounted on said shaft for placement within a tissue mass;means for transmitting rotary or oscillatory motion to said shaft tomove said cutting tip against the tissue to cut tissue fragments fromthe tissue mass; means for removing the tissue fragments along saidshaft by suction to a location outside the body while cutting; and meansfor collecting one or more selected components of the removed tissuefragments for implantation of the fragments into the body of the patientfrom whom they were removed.
 17. An apparatus as defined in claim 16wherein said means for collecting comprises a trap or a filter or astrainer.
 18. An apparatus as defined in claim 16 wherein said flexibleshaft includes surface means defining an axially extending suctionpassage along said flexible shaft through which said tissue fragmentsare removed, said suction passage having a smooth polymeric surface toreduce friction of the removed tissue fragments.
 19. Tissue removalapparatus comprising: a flexible hollow drill shaft; a cutting tipmounted on said shaft; means for transmitting rotary or oscillatorymotion to said drill shaft to move said cutting tip within a tissue massto cut tissue fragments from the tissue mass; means for removing thetissue fragments along said shaft by suction to a location outside thebody while cutting; and guide means for controlling the location of saidcutting tip within the tissue mass.
 20. An apparatus as defined in claim19 wherein said guide means comprises a guide rod extending within saidflexible drill shaft.
 21. An apparatus as defined in claim 19 whereinsaid guide means comprises a hollow guide sleeve outside said flexibledrill shaft.
 22. An apparatus as defined in claim 19 wherein said guidemeans is selectively rigidifiable.
 23. An apparatus as defined in claim19 comprising a second flexible shaft extending generally coaxially withsaid flexible drill shaft and movable with said flexible drill shaftwhen said flexible drill shaft is moved to cut tissue.
 24. An apparatusas defined in claim 19 comprising a formable sleeve extending generallycoaxially about said flexible drill shaft.
 25. Tissue removal apparatuscomprising: a flexible shaft for insertion inside a tissue mass; acutting tip mounted on said shaft for cutting the tissue; means fortransmitting motion to said shaft to move said cutting tip against thetissue to cut tissue fragments from the tissue mass; guide means forcontrolling the location of said cutting tip within the tissue mass;means for removing the tissue fragments along said shaft by suction to alocation outside the body while cutting; and means for collecting one ormore selected components of the harvested tissue fragments forimplantation of the fragments into the body of the patient from whomthey were removed.
 26. A method comprising the steps of: placing withina tissue mass a flexible shaft having mounted thereon a cutting tip forcutting the tissue mass; transmitting motion to said shaft to move saidcutting tip against the tissue to cut tissue fragments from the tissuemass; and removing the tissue fragments along the shaft by suction to alocation outside the tissue mass while cutting the tissue.
 27. A methodas defined in claim 26 further including the step of controlling thelocation of said cutting tip within the tissue mass with a guide rod.28. A method as defined in claim 26 including the step of cutting bonewith a cutting tip which is harder than cancellous bone.
 29. A method asdefined in claim 26 further including the step of collecting one or moreselected components of the removed tissue fragments for implantationinto the body of the patient from whom they were removed.
 30. A methodas defined in claim 29 further including the step of controlling thelocation of said cutting tip within the tissue mass with a guide rod.31. A method of grafting human tissue comprising the steps of obtaininga quantity of tissue fragments suitable for grafting, compressing thetissue fragments into a plug suitable for implantation, and securing thecompressed tissue fragments in the graft location with a retainer.
 32. Amethod as defined in claim 31 wherein the retainer is a biodegradablemesh or sac.
 33. A method as defined in claim 31 wherein the retainer isa mass of solidified flowable polymeric material.
 34. A method asdefined in claim 33 wherein the polymeric material is a biodegradablematerial.
 35. Tissue removal apparatus comprising a rotatable flexibledrill shaft and a rotary cutting tip attached to said shaft forplacement adjacent or within a tissue mass for cutting the tissue, saidrotary cutting tip having first and second adjacent cutting edges spacedapart in the direction of rotation including a leading edge for grabbingthe tissue to be cut and a trailing edge for cutting the tissue.